TD27 Datsun 4x4 glow issue

[yourlocalheadhunter]

I've acquired a datsun td27 4x4. It has been fitted with a temporary glow switch wired to the battery which I dont deal with. So on my journey to find out why the factory system does not work I have hit a brick wall. Things I've tried, new used factory timers, spare relays x2, tested glow plugs. I dont get pre glow of 12v only after glow of around 5v for a short while which is not good enough. Fusible links appear to have continuity. The manifold resistor has 12v in 1 side and 5v in the other side? Can some one shed some light please I cant have this beat me.

[Crash bandicoot]

sounds like the controller is missing the trigger from the ON postiion as opposed to the start position on the key after glow at 5 volt is once the controller knows the engine is being cranked.